Herbicidal compounds, compositions and methods

ABSTRACT

Certain alkylated 1,3- and 1,4-benzenediacetonitriles and 1,3and 1,4-xylylene dihalides are effective selective, preemergence, and postemergence herbicides.

D United States Patent 1 1 1111 3,877,926

Martin Apr. 15, 1975 HERBICIDAL COMPOUNDS, [58] Field of Search 71/105; 260/465 H COMPOSITIONS AND METHODS [76] Inventor: Elmore Louis Martin, 53 Paschal] [56] References Cited Rd., Shellburne, Wilmington, Del. UNITED STATES PATENTS 9803 3,307,933 3/1967 Sasse et a1. 71/105 22 Filed; AP 6 1972 3,504,001 3/1970 Martin 260/465 H 3,574,594 4/1971 Gough et a1. 71/105 21] Appl. No.: 241,800

Related US. Application Data Primary Exami'fe"-Lewis (Fons [63] Continuation-impart of Ser. Nos. 153,429, June 15, Assistant Exammercatherme Mills 1971, abandoned, and Ser. No. 153,427, June 15, 1971, abandoned. [57] ABSTRACT Certain alkylated 1,3- and l,4-benzenediacetonitriles [52] US. Cl. 71/105; 71/7'9; 71/125, and 3 and 4 y y dihalides are effective Selec 71/126 260/465 2 5 tive, preemergence, and postemergence herbicides. 51 Int. Cl A0111 9/20 5 m No Drawings HERBICIDAL COMPOUNDS, COMPOSITIONS AND METHODS CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of my copending applications Ser. Nos. l53,429 and 153,427, now abandoned both filed June 15, 1971.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION It has been discovered that certain 1,3 and 1,4-

d. at least one of R,, R R and R is a C -C alkyl;

e. no nitro groups are ortho to each other;

f. no alkyl groups are ortho to each other;

g. each alkyl group has at most three carbon atoms in straight chain from the point of attachment to the aromatic ring; and l h. when Z is halogen, each of R,-,, R R and R,, is hydrogen.

Accordingly. in one aspect. this invention is a process for selectively controlling undesired vegetation in the presence of crops which comprises preplant soil incorporation, preemergence, or postemergence application of a herbicidally effective amount of a compound of 15 Formula (I).

In another aspect, the invention is a composition for controlling undesired vegetation which comprises a herbicidally effective amount of a compound of Formula l in combination with an inert carrier material.

In yet another aspect, the invention is a group of novel compounds useful as selective herbicides.

DESCRIPTION OF THE INVENTION Compounds of Formula l can be prepared by many processes based on methods generally well known in the art. One method of preparing the compounds of this invention involves replacement of chlorine in 1,3 or l,4-xylylene dichlorides with cyano groups as shown benzenediacetonitriles and 1,3 and l,4-xylylene dihalb l ca cl CHZCN R 1 4 1 C dimethyl Na N su ox e 3 CH CI 3 Cl-l CN ides exhibit selective herbicidal activity and can be used in the presence of valuable crops, e.g.. soybeans, corn, wheat, and rice. These compounds are represented by Formula (I):

Z being the cyano group or halogen, and each of R R.;, R and R independently being hydrogen or methyl;

and each of R,, R R and R, independently is hydrogen, a C -C alkyl, the nitro group, or a halogen; provided that:

a. at most two of R., R R and R are nitro groups;

b. at most two of R R R and R are halogens;

c. at least one of R R R and R is hydrogen or halogen;

Xylylene dichlorides are converted to the corresponding benezenediacetonitriles by reaction with an alkali metal cyanide in a polar solvent such as dimethyl sulfoxide (DMSO).

The preparation of simple xylylene dichlorides is well known to the art and can be achieved using several chloromethylating agents. Simple alkylbenzenes can be bischloromethylated directly with formaldehyde and hydrogen chloride in the presence ofa Lewis acid catalyst such as zinc chloride. For further details see G. A. Club Friedel Crafts and Related Reactions, II, Part 2, Chapter 21 and Organic Reactions, I, 63.

Substituted benzenes having deactivating groups present, such as nitro or halogen groups, can be effectively chloromethylated with chloromethylmethyl ether and percent fuming sulfuric acid. See for example Bull. Chem. Soc. Japan, 43, 3,299-3,30l 1970).

Another process for the preparation of substituted 1,3 and l,4-xylylene dichlorides, necessary for the 0 preparation of the compounds of Formula (1), starts with the corresponding isophthalic and terephthalic acids which are reduced catalytically with hydrogen or with lithium aluminum hydride or diborane in a nonaqueous solvent such as tetrahydrofuran to the corresponding benzenedimethanols; these are converted to the corresponding bischloromethyl compounds by Halogenated benzenediacetonitriles of Formula (I) chlorination of the hydroxyl groups with, for example, can be prepared by chloromethylation of alkylated hydrogen chloride, thionyl chloride, phosphorus oxyhalobenzenes to Xylylene dichlorides with subsequent chloride. phosphorus pentachloride. or oxalyl chloride. conversion to the benzenediacetonitriles. Xylylene di- This reaction sequence is shown below. 5 chlorides can also be halogenated directly [see, for exqgOH CH OH CHgCl R R 1, ,1 1 R1 [c1] 4 1 R \l/ coon R CH OH R CH C1 A number of procedures for the preparation of isoample, Helv. Chim. Acta., 43, 945 (1960)] and then phthalic and terephthalic acids are available from the converted to benzenediacetonitriles. literature. (See for example: Ber., 33, 2377; J. Org. Chem., 18, 1529; J. Am. Chem. Soc., 62, 2327.) Xylylene dibromides, diiodides, and difluorides can These acids can also be prepared from substituted di- 2 also be employed in the preparation of compounds of bromobenzenes as shown in the reaction scheme oute mu fl l Hydrog n bromide Can be Substituted for lined below. hydrogen chloride in the reaction of substituted ben- R R R C OOH BI. Br C CN NC CN A id l 0 u l O liyzrolysis NitrO deri atives Can e ad by t lltl g the berlzenes with formaldehyde to yield Xylylene dibrorhides zenediacetonitriles of formula (1) irectly. -gdirectly. Xylylene difluorides and diiodides can be NCH C NCH C N0 2 j HNO 2 2 cn cn cn cn or, when more advantageous, the intermediate xylylmade by reaction of the corresponding dichloride or ene chlorides or isoand terephthalic acids. A number dibromide with an alkali iodide or alkali fluoride. i

of nitrating agents can be used to effect nitration. For Another Way to prepare the novel compounds of the example, fuming nitric acid, nitric-sulfuric acid mixinstant invention involves alkylation of the methylene tures, and nitronium tetrafluoroborate can all be used. Carbon adjacent to the "mile group alkyl Certain branched secondary alkyl groups such as the ide d Sodium hydride as shown below. isopropyl group can be displaced from the ring during nitration unless these groups are adjacent to or affected CHZCN H C-CH-CN by a strongly election-withdrawing substituent on the i R R ring. For example, 4 1 2;- g% 4 l 3 w CH2CN 3 /L\l/ Q CH CN CH Reactions such as those described are well known in NCHQQ the art, although they may not have been used for the NO preparation of benzenediacetonitriles. A skilled chem- 2 ist would be able to select the most suitable reaction sequence and to determine the optimum reaction condiis obtained by nitration of the corresponding 2,5- ,5 nons' diisopropyl-l,4-benzenediacetonitrile. This displace- The y y dlhallde mtermedlates can be p ment reaction can be used to obtain specific nitrated Sented as Compounds of Structure (I) where A and compounds f F l 1 y are each CH- Z, and Z is halogen. These intermediates,

Preferred because of ease of synthesis and high activity are the compounds of formula (3). below:

CH2CN wherein R and R are each independently alkyl of 2-5 carbon atoms, or the nitro group, provided both are not nitro groups.

lt will be noted that the compounds of Formula (3) are those compounds of Formula (1) wherein each of A and B is the cyanomethyl group, and each of Rg and R is hydrogen. i} i The most active are those compounds of Formula (3 wherein R is alkyl of 3-5 carbon atoms or the nitro group, and R is alkyl'of 3-5 carbon atoms.

The same order of preference applies to the corresponding xylylene dihalide intermediates for the same reasons.

The compounds of this invention are useful as selective preplant incorporation, pree'mergence, or postemergence herbicides. They provide control of many weeds with excellent selectivity in such crops as'corn. soybeans, wheat, cotton, and rice. The compounds are most advantageously applied pree'mergenee at rates of 0.25 to pounds per acre, dependingjon the crop, the weed to be controlled, the soil and environmental conditions and the particular chemical used. Under certain conditions, such a lack of rainfall for an extended period after application, it is advantageous to lightly soil incorporate these compounds. Selected members of this class of compounds have postemergence activity and may be used-at rates of 1 to 10 kg/ha for postemergence weed control, if applied while susceptible weeds are young, preferably in the two-leaf stage of development. Two or more herbicides of the present invention can be used simultaneously.

Weeds controlled include crabgrass (Digitaria spp). barnyardgrass (Echinochloa crusgalli), junglerice (Echinochloa co'lonum foxtail (Semi-fa spp.),' witchgrass (Pam'jcum capillure), goosegrass (Eleusine indica). pigweed (Amaramhus ret'troflexusi," wild "mustard (Brassica spp), curly dock (Rumex crispus), johnson grass (Sorghum'halepense) from s'eed,cheat (Bromus secalinus), downy brome(Bi*Qnuls rector-um) and blackgrass (Alopucurus*mysiimides)'=.- a

It issometimes -adv antageous to combine a-compound of this invention with another herbicideinorder to increase the spectrum of weeds controlledand tominimize the chances'of injury to. thecurrent or subsequent crops. The exact combination which maybe used (Polyganunr to the best advantage willdepend upon the crop. the weeds to be controlled and the environment in which the crop, is growing. but can'be readily selected by one with ordinary skill in the art. The use of those herbicides in combination with the herbicides of this invention will provide control of a wide variety of broadleaved weeds including ragweed (Ambrosia spp). lambsquarter (Chenopmlimn album), morningglory (Ipomeu spp). sicklepod (Cassia obtusififlia). smartwecd spp), .flower-of-an-hour (Hibiscus trionum). cocklebur (Xanthium spp), and velvet-leaf (Almlilon llwuphmsli). as well as grasscs.

The herbicidal compositions of this invention containing mixtures with other herbicides can be formulated as-such. Alternatively. the compounds of Formula l may be tank-mixed with other known herbicides or applied sequentially with other known herbicides.

Among the known herbicides which can be combinedwith the compounds of Formula (1) are:

SUBSTITUTED UREAS 3-( 3,4-dichloroph'enyl -1 ,l-dimethylurea 3-( 4-chlorophenyl 1', l -dimethylurea 3-phenyl-IJ-dimethylurea 3-(4-chlorophenyl)-l-methoxy-l-methylurea 3-( 3,4-dichlorophenyl )-l l,3-trimethylurea 3-( 3,4-dichlor0phenyl )-l l -diethylurea 3-(p-chlorophenoxyphenyl)-l.l-dimethylurea N-cyclooctyl-N'-dimethylurea 3-(4-chlorophenyl)-l-methyl-l-(l-methyl-Z- propynyl )urea 3-(4-bromo-3-chlorophenyl l -methoxyl methylurea 3-[p-(p-chlorophenoxy)phenyl]-l l -dimethylurea 40 3-( 4-trifluoromethylphenyl)- l l -dimethylurea 3-(4-bromophenyl l -methoxyl -methylurea 3-( hexahydro-4,7-methanoindan-5-yl l l dimethylurea l-( Z-methylcyclohexyl )-3-phenylurea 3 (p-cumenyl)-l.l-dimethylurea These ureas can be mixed with the compounds of Formula (1) in weight proportions of from 1:40 to 10:1, the preferred ratio being M2 to 4:1.

SUBSTITUTED TRIAZINES 2-chloro-4,6-bis(ethylamino)-s-triazine 2-chloro-4-ethylamino-6-isopropylamino-s-triazine 2-chloro-4,6-bis( methoxypropylamino )-s-triazine 2-methoxy-4,6-bis(isopropylamino)-s-triazine 2-diethylamino-4-isopropylacetamid0-6-methoxy-striazine 2-isopropylamino-4-methoxyethylamino-6- methylmercapto-s-triazine Z-methylmercapto-4,6-bis(isopropylamino)-striazine 2-methylmercap to-4,6-bis(ethylamino)-s-triazine 2-meth-ylmercapto-4-ethylamino-6-isopropylaminos-triazine 2-methoxy-4,6-bis(ethylamino)-s-triazine 2-methoxy-4-ethylamino-6-isopr0pylamino-s-triazine 2-'chloro-4,6-bis( isopropylamino )-s-triazine 2-methoxy-4,6-bis( isopropylamino )-s-triazine 7 2-ethy1amino-4-isopropylamino-6-methy1m ercaptos-triazine 2-chloro-4-chloropropylamino--isopropylamino- 1,3 ,S-triazine 2,4-bis( isopropylamino )-6-methylmercapto-striazine Z-tert-butylamino-4-ethylamino-b-methylthio-striazine These triazines can be mixed with the compounds of this invention in the weight proportions of from 1:40 to 10:1, the preferred ratio being 1:12 to 4:1.

PHENOLS 3,5-dinitro-o-cresol 4.6-dinitro-o-sec-butylphenol and its salts 4.6-dinitro-o-sec-amylphenol pentachlorophenol and its salts These phenols can be mixed with the compounds of this invention in the weight proportions of from 1:10 to 10:1, the preferred ratio being 1:5 to :1.

SUBSTlTUTED URAClLS 3-isopropyl-5-bromo-6-methy1uracil 5-brom0-3-sec-butyl-6-methyluraeil 3-tert-butyl-5-chloro--methyluracil 5-chloro-6-methyl-3-neopentyluracil 3-tert-butyl-5-bromo-6-methyluracil 3-isopropyl-5-chloro-6-methyluracil 3-tert-butyl-S-ch1oro-6-ethy1uracil 3-tert-butyl-5-chloro-6-chloromethyluracil 3-cyclohexy1-6-methyluracil 3-cyclohexyl-6-ethyluracil 3-cyclohexyl-6-sec-butyluracil 3-norborny1-6-methyluracil 3-cyclopentyl-6-methyluracil 3-cyclohexyl-6-isopropyluracil 3-cyclohexyl-5 ,6-trimethyleneuracil 3-sec-butyl-5,6-trimethyleneuracil 3-isopropyl-5.-trimethyleneuracil 3-isopropyl-5.-tetramethylencuracil 3-isopropyl-5.6-pentamethyleneuracil 3-cyclohexyl-5-bromouracil 3-cyclohexyl-5-chlor0uracil 3-is0propyl-5-brom0uracil 3-sec-butyl-5-bromouracil 3-sec-butyl-S-chlorouracil 3-isopropyll -trichloromethylthio-5-br0m0-6- methyl-uracil 3-cyclohexyll -trich1oromethylthi0-5-bromo-6- methyluracil 3-sec-butyl-1-acetyl-5-br0mo-6-methyluracil 3-isopropyll -acety1-5-bromo-6-methyluracil 3-isopropyl- 1 -trichloromethylthio-5 -chloro-6- methyluracil These substituted uracils can be mixed with the com- 5 pounds of this invention in the weight proportions of from 1:80 to :1, the preferred ratio being from 1:20

CARBOXYLlC ACIDS AND DERIVATIVES The following carboxylic acids and derivatives can be mixed with the compounds of this invention in the listed weight proportions:

A. 2.3,6-trichlorobenzoic acid and its salts 2,3,5,6-tetrachlorobenzoic acid and its salts 2-methoxy-3,5,6-trichlorobenzoic acid and its salts 2-methoxy-3,6-dichlorobenz0ic acid and its salts 2-mcthoxy-3,5,6-trichlorobenzoie acid 3'-amino-2,5-dich1orobenzoic acid and its salts 3-nitro-2,5-dichlorobenzoic acid and its salts 2-methy1-3,o-dichlorobenzoic acid and its salts 5 4-chlorophenoxyacetic acid and its salts and esters 2,4-dichlorophenoxyacetic acid and its salts and estcrs 2,4-dichlorophenoxyethylsulfate 2.4,S-trichlorophenoxyacetic acid and its salts and I0 esters (Z-mcthyl-4-chlorophenoxy)acetic acid and its salts and esters (2-methyl-4-chlorophenoxy)propionic acid and its salts and esters 2-(2.4,5-trichlorophenoxy)propionic acid and its salts and esters 2-( 2,4,5-trichlorophenoxy )ethyl-2,2-

dichloropropionate 4-( 2,4-dichlorophenoxy)butyric acid and its salts and esters 4-(2-methyl-4-chlorophenoxy)butyric acid and its salts and esters 2,3,6-trichlorobenzyloxypropanol 7s tris(2,4-dichlorophenoxyethyl)phosphite Mixed in a 1:80 to 8:1 ratio, preferably a 1:20 to 2:1 ratio. B. 2,6-dichlorobenzonitrile 3.5-dibromo-4-hydroxybenzonitrile Mixed in a 1:40 to 4:1 ratio, preferably a 1:16 to 3:1 ratio. C. trichloroacetic acid and its salts Mixed in a 1:8 to 8:1 ratio, preferably a 1:4 to 4:1 ratio. D. 2,2-dichlor0propionic acid and its salts 2-( a-naphthoxy )-N,N-diethylpropionamide 2-(4-ch1oro-6-ethylamino-2-ylamino)methylpropionitrile Mixed in a 1:8 to 8:1 ratio, preferably a lc4 to 4:1 ra- 4 tio.

E. N,N-di(n-propyl)thiolcarbamic acid, ethyl ester N,N-di(n-propyl)thiolcarbamic acid, n-propyl ester N-ethyl-N-(n-butyl)thiolcarbamic acid, ethyl ester N-ethyl-N-(n-butyl)thiolcarbamic acid, n-propyl 5 ester S-2,3-dichloroal1yl-N,N-diisopropylthiolcarbamate 5-2.3,3-trichloroallyl-N,N-di-isopropylthiolcarbamate S-propyl-n-butylethylthiocarbamic acid 2-chloroallyldithiocarbamate S-ethyl diisobutylthiocarbamate 2-chloroallyldiethyldithiocarbamate S-ethyI-N-ethylthiocyelohexanecarbamate Mixed in a 1:4 to 4:1 ratio, preferably a 1:2 to 2:1 ra- 5 tio.

F. N-phenylcarbamic acid, isopropyl ester N-( m-chlorophenyl)carbamic acid, isopropyl ester N-(m-chlorophenyl)carbamic acid, 4-ch1oro-2- butynyl ester N-(3,4-dichloropheny1)carbamic acid, methyl ester N-( 3,3-dimethylureido )phenyl-tert-butylcarbamate 2,6-di-tert-butyl-p-tolylmethylcarbamate Mixed in a 1:8 to 8:1 ratio, preferably a 1:4 to 4:1 ratio.

G. 2,3,-trichlorophenylacetic acid and its salts Mixed in a 1:4 to 8:1 ratio, preferably a 1:4 to 4:1 ratio.

9 H. 2-chloro-N,N-diallylacetamide maleic hydrazide l,2-dihydropyridazine-3 ,6-dione 3,4-dichloro-2-methacrylanilide 2-chloro-2',6-diethy1-N(methoxymethyl )acetanilide N-( butoxymethyl )-2-ch1oro-2,6'-diethylacetanilide 3,5-dinitro-N',N'-dipropylsulfanilamide 2-chloro-N-isopropylacetanilide 3',4-dichloropropionanilide Mixed in a 1:8 to 10:1 ratio, preferably a 1:4 to :1 ratio. 1. 4-amino-3,5.6-trichloropicolinic acid Mixed in a 1:100 to 4:1 ratio. preferably a 1:20 to 2:1 ratio.

INORGANIC AND MIXED INORGANIC-ORGANIC SALTS The following salts can be mixed with the compounds of this invention in the listed weight proportions: A. monoammonium methanearsonate calcium methylarsonate calcium propylarsonate disodium monomethylarsonate octyl-dodecylammoniummethylarsonate dimethylarsinic acid hydroxydimethylarsine oxide Mixed in a 1:8 to 4:1 ratio, preferably a 1:4 to 2:1 ratio. B. sodium arsenite potassium cyanate Mixed in a 1:10 to 20:1 ratio, preferably a 1:5 to :1 ratio. C. lead arsenate calcium arsenate Mixed in a 10:1 to 100:1 ratio, preferably a 20:1 to 50:1 ratio. D. sodium tetraborate hydrated, granulated sodium metaborate sodium pentaborate polyborchlorate unrefined borate ore such as borascu Mixed in a 10:1 to 600:1 ratio, preferably a 20:1 to 400:1 ratio. E. ammonium thiocyanate Mixed in a 1:10 to 10:1 ratio, preferably a 1:5 to 5:1 ratio. F. sodium chlorate Mixed in a 10:1 to 200:1 ratio, preferably a :1 to 100:1 ratio. G. ammonium sulfamate Mixed in a 1:1 to 200:1 ratio, preferably a 2:1 to 100:1 ratio.

OTHER ORGANIC HERBICIDES 6,7-dihydrodipyrido[1,2-a;2 ,l '-c]pyrazinediium Mixed in a 1:20 to :1 ratio, preferably a 1:10 to 10:1 ratio.

C. 3,6-endoxohexahydrophthalic acid Mixed in a 1:10 to 20:1 ratio, preferably a 1:4 to 10:1

ratio.

D. hexachloroacetone Mixed in a 1:8 to 16:1 ratio, preferably a 1:4 to 8:1

ratio.

E. diphenylacetonitrile N.N-dimethyl-ma-diphenylaeetamide N.N-di-n-propyl-2,6-dinitro-4-trifluoromethylaniline N,N-di-n-propyI-2.6-dinitro-4-methylaniline 2,6-dinitro-N,N-di(2-chloroethyl)-p-toluidine 4-(methylsulfonyl)-2,o-dinitro-N.N-dipropylaniline N-sec-butyl-4-tcrt-butyl-2,6dinitroaniline 4-isopropyl-2,o-dinitro-N,N-dipropylaniline Mixed in a 1:10 to 10:1 ratio, preferably a 1:5 to 5:1

ratio.

F. O-( 2,4-dichlorophenyl )-O-methylisopropylphosphoramidothiate 0.0-diisopropylphosphorodithioate-S-ester with N- (2-mereaptoethyl )benzenesulfonamide S-ethylhexahydro-l-H azepine-l-carbothioate 2.3,5,o-tetrachloroterephthalic acid, dimethyl ester Mixed in a 1:20 to 20:1 ratio, preferably a 1:10 to 10:1 ratio.

G. 2,4-dichlorophenyl-4'-nitrodiphenyl ether 2,4-dinitro-4-trifluoromethyldiphenylether Mixed in a 1:20 to 10:1 ratio, preferably a 1:10 to 5:1

ratio.

H. N-l-naphthylphthalamic acid and its salts Mixed in a 1:8 to 20:1 ratio, preferably a 1:4 to 10:1

ratio.

1. 3-chloro-2-methy1-p-valerotoluidide 2-chloro-N-(ethoxymethyl)-6-ethyl-O- acetotoluidide N-butyl-N-ethyl-a,a,a-trifluoro-2.6-dinitro-ptoluidine Mixed in a 1:10 to 10:1 ratio, preferably a 1:5 to 5:1 ratio. J. 3,3a-dihydro-2-(p-methoxyphenyl) 8H- pyrazolo(5,l-A)-isoindol-8-one 2-[3-(4-methoxyphenyl)-5-pyrazolyl)benzoic acid 2-( 3-phenyl-5-pyrazolyl )benzoic acid Mixed in a 1:20 to 8:1 ratio, preferably a 1:10 to 4:1 ratio.

The preparation of representative benzenediacetonitriles and xylylene dihalides of the present invention is illustrated in the following examples, in which all parts, proportions, and percentages are by weight, unless indicated otherwise.

EXAMPLE 1 Preparation of 2-Ethyl-l,3-Xylylene dichloride PART A 2-Ethylisophthalonitrile A mixture of 78 parts of 2,6-dibromoethylbenzene, 75 parts of cuprous cyanide and parts of N- methylpyrrolidinone is stirred mechanically and heated at 210C for 5 hours, then concentrated under reduced pressure to one-fifth volume. The mixture is poured slowly with stirring into a mixture of 60 parts of sodium cyanide in 300 parts of water and 800 parts of ether. The mixture is stirred 0.5 hour, then the ether layer is separated and washed with 10 percent aqueous sodium cyanide and saturated sodium chloride solution, dried and concentrated. The residue is distilled to afford 2- ethylisophthalonitrile.

PART B Z-Ethylisophthalic Acid A mixture of 60 parts 2-ethylisophthalonitrile and 300 parts of 50 percent sulfuric acid is stirred and refluxed l hours, then cooled and filtered. The isolated solid is dissolved in percent aqueous sodium hydroxide and washed with ether. The aqueous layer is acidified with dilute hydrochloric acid and filtered. The isolated solid is crystallized from a suitable solvent to afford Z-ethylisophthalic acid.

PART C Z-Ethyl-l ,3-benzenedimethanol To a suspension of 38 parts of lithium aluminum hydride in 200 parts of anhydrous tetrahydrofuran is added dropwise a solution of 97 parts of 2- ethylisophthalic acid in tetrahydrofuran. The resulting solution is refluxed 2 hours, cooled in an ice bath and the excess lithium aluminum hydride is destroyed by addition of ethyl acetate. The mixture is diluted with 500 parts of ether, washed sequentially with dilute hydrochloric acid, dilute sodium hydroxide, and saturated sodium chloride solution. The organic phase is separated. dried and concentrated to afford 2-ethyl-l,3- benzenedimethanol.

PARTD 2-Ethyl-l .3-xylylene dichloride To a solution of 21 parts of 2-ethyl-l.3-

benzenedimethanol in 150 parts of benzene is added a catalytic amount of dimethylformamide and dropwise 30 parts of thionyl chloride. The mixture is refluxed until evolution of gas ceases, then concentrated to afford suitably pure 2-ethyl-l ,3-xylylene dichloride.

By the reaction sequence of Example 1, Parts AD, the following monoalkyl l,3- and l,4-xylylene dichlorides (Table I) can be prepared from the listed alkyldibromobenzenes.

TABLE I Starting Material Product 2-propyll .3-xylylene dichloride Z-isopropyll .3-xylylene dichloride Z-sec-butyl-l .3xylylene dichloride IZ-tert-butyll .3-xylylene dichloride Z-isobutyl-l ,3-xylylene dichloride 2.6-dibromopropylhenzene 2.6-dihromoisopropylhen2ene 2,6-dibromo-see-butylbenzene 2,o-dibromo-tert-butylbenzene 2,-dibromoisohutylbenzene 2-Bromo-l ,3-diethylbenzene A solution of [4.9 parts of 2,6-diethylaniline in 125 parts of concentrated hydrobromic acid is cooled to 0C and a solution of 6.9 parts of NaNO in 10 parts of water is added slowly beneath the surface. The resulting diazonium salt solution is stirred at 0C for 0.2 hrs then added portionwise to a solution of 13 parts of cuprous bromide in 50 parts of 48 percent hydrobromic acid held at l l0l40C. The resulting mixture is stirred 5 min then diluted with water. The organic phase is extracted with methylene chloride, washed sequentially with concentrated hydrochloric acid, water, l0 percent aqueous sodium hydroxide and again with water. The methylene chloride solution is dried and fractionated, affording essentially pure 2-br0mo-l,3- diethylbenzene as one of the fractions.

PART B 2,6-Diethylbenzoic Acid PA RT C 3-Bromo-2,6-diethylbenzoic Acid To a solution of 17.8 parts of 2,6-diethylbenzoic acid and 3 parts of iron powder in 300 parts of chloroform is added portionwise, with cooling and exclusion of light, 16 parts of bromine in 25 partsof chloroform. The mixture is stirred at 25C for 1 hr then refluxed for 3 hrs. The resulting solution is freed of solvent by vacuum distillation and the residue is taken up in hot 10 percent sodium hydroxide solution. The cooled basic.

solution is washed with ether and acidified. The resulting precipitate is collected, washed with water and recrystallized from a suitable solvent, affording essentially pure 3-bromo-2,o-diethylbenzoic acid.

PART D Methyl 3-bromo-2,6-diethylbenzoate A mixture of 25.7 parts of 3-bromo-2,6- diethylbenzoic acid, 5 parts of concentrated sulfuric acid and 32 parts of methanol is refluxed for 1 hr. The cooled reaction mixture is diluted to three times its volume with methylene chloride. The aqueous layer is separated, and the methylene chloride solution is shaken with water, and then with sodium carbonate solution until neutral, and again with water. The organic phase is dried and the solution concentrated in vacuo. The residue is fractionated affording pure methyl 3-bromo-2,6-diethylbenzoate as one of the fractions.

PART E Methyl 3-cyano-2,6-diethylbenzoate To a solution of 27.1 parts of methyl-3-bromo-2,6- diethylbenzoate in 50 parts of N-methylpyrrolidinone is added 9 parts of cuprous cyanide. The mixture is heated to 200C for 1 hr, cooled and transferred to 200 parts ice water. The resulting solid is collected, washed; with water and transferred to 100 parts fresh water to which is then added a solution of 50 parts potassium cyanide in parts of water. The mixture is stirred for 5 minutes; then, 300 parts of methylene chloride is added. and stirring additional hour. The methylene chloride solution isiscparated washed with water, dried; decolorizedand concentrated. The residue is fractionally distilled affording essentially pure methyl 3-cyano-2,o-diethylbenzoate as one of the fractions. g

PART F 2.4-Diethylisophthalic Acid A mixture of 22. parts of methyl 3-cyano-2,6diethylbenzoate and 50 parts of 100 percent sulfuric acid is warmed on a steam bath for 1 hr. then poured into ice water. The resulting precipitate is collected, washed with water and taken up on percent sodium hydroxide. The basic solution is washed with ether and acidified. The resulting essentially pure 2,4-

diethylisophthalic acid is collected, washed with water and dried.

TABLE [I Starting Material Product 2-bromo-3-tert-hutyltoluene 4-tert-butyl-2-methyl-1.3-xylylene dichloride Z-bromo-B-ethylcumene 2-ethyl-4-isopropyl- I .3-xylylene dichloride 2-bromo-l .3 'cusapropylbenzene 2.4-diisopropyll .3-xylylene dichloride 2-bromol .3-di-tert- 2.4-di-tert-hutyl-l ,3xylylene butylbenzene dichloride 2bromo-3-tert-butylcumene 4-tert-butyl-2-isopropyll .3-

xylylene dichloride Z-bromo-3-tert-butylpropylhen zene 2-bromo l .3-di-secbutylbenzene 2-bromo-( l. 1 ,2 2- tetramethylpropyl )ethylbenzene 2-bromo-3-( LI .2

trimethyl )cumene 2-bromo 3 tert-pentylisobutylbenzene 2-bromo-3-secbutylisobutylhenzene Z-bromo-3-sec-butylcumene 4-terthutyl-2'propyll .3-xylylene dichloride 2.4-di-sec-butyl-l .3-xylylene dichloride 2-ethyl-4-( 1.1.2.2-tetramethylpropyl )-l .3-xylylene dichloride 2-isopropyl-4-( 1,1 .2-trimethylpropyl l .3-xylylene dichloride 2-isobutyl-4-tert-pent)'ll .3-xylylene dichloride 4-sec-butyl-2-isobutyll .3-xylylene dichloride 4-see-hutyl-2-isopropyll .3'xylylene dichloride EXAMPLE 3 Preparation of 2,5-Diisobutyl-1,4-xylylene dichloride A suitable reaction vessel is charged with 26 parts of p-diisobutylbenzene, 9 parts of paraformaldehyde and 9 parts of zinc chloride. A rapid streamof dry hydrogen chloride is passed into the vigorously stirred mixture at 55-60C. Three parts of paraformaldehyde and 3 parts of zinc chloride are added at 1.5 hr. intervals four times. After the last addition, the reaction is continued for 1 /2 hrs. then the mixture is cooled to room temperature. diluted with water and ether. The organic layer is separated, washed three times with dilute hydrochloric acid and once with saturated sodium bicarbonatesolu tion. The organic phase is dried and concentrated. Pentane is added to the residue and small amounts of insolubles are separated. The solution is cooled slowly to -C. The resulting colorless crystals are collected affording 22 parts of 2.5-diisobutyl-l,4-xylylene dichloride having m.p. 33-34C.

The following 1.3 and l,4-xylylene dichlorides can be prepared by substituting the listed aromatic hydrocarbon for p-diisobutylbenzene of Example 3.

TABLE III Starting Material Product p-diisopropylbenzene lS-diisopropyh l .4 xylylene dichloride. m.p. l29l3lC 2.5dipropyll .4-xylylene dichloride 2.5-di-sec-hutyl-l .4-xylylene dichloride. b.p. l l2C'/()il mm p-dipropylhe nzene p-di-sec-hutylhenzene m-terbbutylcumene 4-tert-butyl-6-isopropyl l .3-

xylylene dichloride 4-tert-butyl-6-isobutyl l .3 xylylene dichloride 4-sec-butyl-o-tert-butyll .3-xylylene dichloride 4.6 di-tert-butyll .3 xylylene dichloride 4.6-diisobutyll .3-xylylene dichloride 4.6-di-sec-butyll .3-xylylene dichloride 4.6-dipropyll .3-xylylene dichloride 4-isobutyl-6-isopropyl-l .3-xylylene dichloride 4-sec-butyl-o-isopropyll 3xylylene dichloride 4-isopropyl-o-tert-pentyl-l .3

m-tert-butylisohutylbenzene m-sec-butyl-tert-butylbenzene mdi-tert-butylbenzene m-diisobutylbenzene m-di-sec-butylbenzene m-dipropylbenzene m-isohutylcumene m-sec-butylcumene m-tert-pentylcumene m-( l l .2.2-tetramethylpropyl toluene m-( l. l .Z-trimethylpropyl )ethylbenzene m-sec-butylisobutylbenzene m-propylcumene m-neopentylcumene xylylene dichloride 4-methyl6-( l. l .2.2-tetramethylpropyl l .3-xylylene dichloride 4-ethyl6-( l. l ,Z-trimethylpropyl l.3-xylylene dichloride 4-secbutyl6-isobutyl-l .3-xylylene dichloride 4-isopropyl-6-propyll .3-xylylene dichloride 4-isopropyl6-neopentyll .3- xylylene dichloride When the alkyl groups of the p-dialkylbenzene are different and one is a primary alkyl group and the other a secondary or tertiary alkyl group, two isomers are obtained. A 2,5-dialkyl-1,3-xylylene dichloride is obtained along with smaller amounts of a 2,5-dialkyl-l ,4- xylylene dichloride. When the alkyl groups are different and either secondary or tertiary, a mixture of 2,5-dialkyl-l,3-xylylene dichloride and 2,5-dialkyl-l ,4- xylylene dichloride is obtained the ratio of isomers depending on the branched alkyl groups present. The isomers can be separated from these mixtures by fractional crystallizations, fractional distillations and chromatography. The mixtures are also useful both as intermediates to benzenediacetonitriles and as herbicides in their own right.

EXAMPLE 4 Preparation of S-tert-Butyl-2-isopropyl-l ,3-xylylene 15 dichloride and Z-tcrt-Butyl-S-isopropyll ,4-xylylene dichloride Into a mixture of 880 parts p-tert-butylcumene, 300 parts paraformaldehyde, and 300 parts of zinc chloride is passed dry hydrogen chloride at 65C until the mixture is saturated. The mixture is stirred at 7073C for 1 hour. Additional 300 parts of paraformaldehyde and 300 parts of zinc chloride are added. The mixture is again saturated with hydrogen chloride and stirred 1 hour at 7073C, then the final addition of 300 parts of paraformaldehyde and 300 parts of Zinc chloride is made. The resulting mixture is stirred at 70-73C with continuous passage of hydrogen chloride through it for 22 hours. To the mixture are added 250 parts of ice and 2,400 parts of concentrated hydrochloric acid. The mixture is separated and extracted with pentane. The organic phase is washed sequentially with concentrated hydrochloric acid, 6N hydrochloric acid, sodium bicarbonate solution and water. The organic phase is sepa- TABLE IV TABLE V Starting Material Product 2.5-diisopropyl-l .4-xylylene dihromide lS-diisobutyl-1.4-xylylene dihromide 2.5-di-tert-butyl-1.4-xylylene dihromide Z-isohutyl-S-isopropyll .4-xylylene dihromide Z-tert-butyl-5'isopropyll ,4- xylylene dihromide Z-methyl-S-neopentyl-l .J-xylylene p-diisopropylhenzene p-diisohutylhenzene p-di-tert-hutylhenzene p-isobutylisopropylhenzene p-tert-hutylisopropylbenzene p-ncopentyltoluene dihromide p-di-sec-but \'lhenzene 2.5-di-sec-butyll .4-xylylene dihromide m-tert-hutylethylbenzene 4-tert-butyl-6-ethyll .3-xylylene dibromide m-tert-hutylcumene m-tert-hutylisohutylhenzene l.3 di-ten-hutylhenzene l.3-diisohutylbenzene LB-di-sec-hutylhenzene EXAMPLE 5 Preparation of 5-lsobutyl-l .3-Xylylene difluoride Starting Material Product p-tert-pentyltoluene p-tert-hutyltoluene p( l. l .Z-trimethylpropyl )toluene Z-methyl-S-tert-pentyll .B-xylylene dichloride 2-methyl-S-tert-pentyll .4- S-Ien-hutyI-Z-methyI-I.3 Z-tert-butyl-S-methybl .4-xylylene dichloride 2-methyl-S-( l l .2-trimethylpropyl )-I .3-xylylene dichloride l\-lene dichloride lene dichloride. m.p. 75-76 2-methyl-5-( l. l .Z-trimethylpropyl l .4-xylylene dichloride p-tert-hutylethylhenzene p-ethyl-tert-pentylhenzene p-( l 2-dimethylpropyl )ethylhenzene S-tert-butyl-Z-ethyl-1.3-xylylene dichloride Z-tert-butyl-S-ethyll .4-x y Z-ethyl-S-tert-pentyl-l .3- 2-ethyl-5-tert-pentyl 1 .4- 5-( LZ-dimethylpropyl l-Z-ethyll .3-xylylene dichloride lene dichloride 'l\'lene dichloride xflylene dichloride 2-( l .Z-dimethylpropyl )-5cthyll .4-xylylene dichloride p-( I ,l .Z-trimethylpropyl )ethylhenzene p-tert-butylpropylhenzene Z-ethyl-S-l l l .Z-trimethylpropyl )-l .3-xylylene dichloride Z-ethyl-S-l l.l .Z-trimethylpropyl )-l .4-xylylene dichloride 5-tert-hutyl-2-propyl-l .3-xylylene dichloride Z-tert-hutyl-S-propyll .4-xylylene dichloride p-tert-pentylpropylbenzene 5 tert-pentyl-Z-propyl-1.3-xylylene dichloride Z'tert-pentyI-S-propyl l .4-xylylene dichloride p-( 1.2.2-trimethylpropyl )propylbenzene p-( l.l .Z-trimethylpropyl )propylbenzene p-propylcumene Z-rsopropy p-isohutylcumene 2-isobutyl- Z-isohutvlp-sec-hutylcumene Z-sec-butyl-5-isopropyll .4-xvlylene dichloride p-tert-pentylcumene p-t l.l .Z-trimethylpropyl )cumene S-tert-pentyl-Z-isopropy 2-tert-pentyl-Sdsopropy l-L3- ll .4-xylylene dichloride 2-isopropyl-5-( l. l .Z-trimethylpropyh-1.3-xylylene dichloride lvlene dichloride Z-isopropyl-S-l l. l .l-trimethylpropyl l .4-xylylene dichloride p-( l.l.3.Z-tetramethylpropyl )cumene p-te rt-hutylisobutylhenzene Z-tert-hut sohutyl-l .4- S-Iert-butyl-Z-neopcntyl-l 2-tert-butyl-5-neopentyl- Z-sec-hutyl-S-tert-hutyll .3-x

Z-sec-butyl-S-tert-hutyl-l .4-xylylene dichloride 5-tert-but \'l2-( ll'dimethylpropyl l .3-xylylene dichloride 2-tert-butyl-5-( ll-dimethylpropyl l ,4-xylylene dichloride propyl-l .3-

p-tert-butylneopentylbenzene p-seohutyl-te rt-butylhenzene p-( LZ-dimethylpropyl )tert-hutylhenzene p-seohutylpropylbenzene S-sec-hutyl-Z- Z-sec-huty 5 p-sec-hutylisohutylbenzene I Z-sec-buty cymene sobutyl-l S-isopropyl-'l-methyl' I .3 2-isopropyl-S-methyll .4

-tetrameth vlpropyl )-l .3-xylylene dichloride 2.2-tetramethylpropyl )-l .4-xylylene dichloride sohutyll .lLxylylene dichloride lene dichloride lylene dichloride 'l \'lene dichloride lene dichloride 'lvlene dichloride lvlene dichloride 7 aylylene dichloride A mixture of 23.] parts of S-isobutyl-l,3-xylylene dichloride and 10 parts of potassium fluoride in 50 parts of tetramethylene sulfone is stirred at 100C for 12 hrs then cooled and poured into ice water. The resulting organic phase is extracted with ether. washed with water and dried. The solvent is removed under reduced pressure and the residue distilled affording essentially pure -isobutyl-l .3-xylylene difluoride.

EXAMPLE 6 Preparation of 4-lsopropyl-6-isobutyl-l .3-xylylene diiodide A mixture of 3.6 parts of 4-isopropyl-6-isobutyl-1.3- xylylene dichloride and 3.2 parts of potassium iodide in parts of tetramethylene sulfone is stirred at lO0C- for 24 hrs, then cooled and poured into ice water. The organic phase is extracted with ether. washed withwater and dried. The solvent is removed under reduced pressure. The residue is passed through a column chromatograph packed with silica gel or Florisil from which is isolated pure 4-isopropyl-6-isobutyl-l,3-xylylene diiodide as one of the fractions.

Other 1,3 and l,4-xylylene diiodides and xylylene difluorides can be prepared by contacting the listed xylylene dichlorides with the appropriate alkali iodide or fluoride by the procedures of Examples 5 or 6.

TABLE VI Starting Material Product 4,6-diisobutyll .3-xylylene 4.6-diisobutyll .3-xylylene dichloride difluoride 4.6-di-tert-butyll .3-xylylene 4,6-di-teit-hutyll .3-xylylene dichloride difluoride 4,6-di-sec-hutyll .3-xylylene 4.6-di-sec-hutyl-l .3-xylylene dichloride difluoride 4.6-diisopropyl-l .3-xylylene 4,6-diisopropyll .3-xylylene dichloride difluoride 4-tert-hutyl-6-isopropyl-l ,3- xylylene dichloride 4-isohutyl-o-isopropybl .3-

xylylene dichloride difluoride Z-tert-hutyl-S-methyll .4- Z-tert-hutyl-S-methyl-1.4-xylylene xylylene dichloride difluoride 2.5-diisobutyl-l .4-xylylene 2.5-diisohutyll .4-xylylene dichloride difl uoride 2.5-di-tert-hutyl- I .4-xylylene 2.5-di-tert-butyl-l .4xylylene dichloride difluoride Z-tert-hutyl-S-isopropyl-l .4- xylylene dichloride 3-tert-butyl-5-ethyll .4-xylylcne Z-tert-butyLS-isopropyll .4- xylylene difluoride B-tert-butyl-S-ethyll .4-xylylene dichloride difluoride 4,6-diisohutyll .3-xylylene 4.6-diisohutyll .3-xylylene diiodide dichloride 4.6-di-tert-hutyl-l .3-xylylene 4.6-di-tert-butyl-l .3xylylene dichloride diiodide 4-tert-butyl-o-isopropyll .3- xylylene dichloride 4-tert-butyl-o-isobutyl-1,3

4-tert-hutyl-fvisopropyll .3- xylylene diiodide 4-tert-hutyl-6-isoh utyll .3-xylylene 2,4-Diethyl-6-isopropyl-I,3-xylylene dichloride A mixture of l8 parts of l,3-diethyl-5-isopropylbenzene and 32 parts of ehloromethyl methyl ether is diluted with 60 parts of carbon disulfide and cooled to 0C. To the stirred solution is added 18 parts of stannic chloride. The reaction is stirred at room temperature for 6 hours. It is poured on ice and the organic layer is separated and dried. Removal of the solvent and distillation of the residue gives 2,4-diethyl-6-isopropyl-l.3- xylylene dichloride.

The listed xylylene dichlorides are prepared from the appropriate trialkylbenzenes as follows:

TABLE Vll Starting Material Product l.3.5-triisopropylbenzene l.3.S-tri-seobutylbenzene S-isopropyll .3- dimethylhenzene S-tert-hutyl- 1.3- dimethylhenzene S-Iert-hutyll .3-diethylhenzene EXAMPLE 8 Preparation of 3,5-Dipropyl-l,4-xylylene dichloride PART A 3,5-Dipropylterephthalic Acid This compound is prepared according to the procedure of Gilman et.al., J. Am. Chem. Soc. 62, 2332 (1940).

To a solution of 32 parts of l,4-dibromo-3.5- dipropylbenzene in parts of hexane is added 26 parts of n-butyllithium. The mixture is refluxed 20 hours then is cooled and poured onto excess solid carbon dioxide. The resulting solid is recrystallized to give 3.5-dipropylterephthalic acid.

PART B 3,5-Dipropyl-l ,4-benzenedimethanol To a suspension of 38 parts of lithium aluminum hydride in 200 parts of anhydrous tetrahydrofuran is added dropwise a solution of parts of 3.5- dip-ropylterephthalic acid. The resulting mixture is refluxed 2 hours, cooled in an ice bath. and ethyl acetate added slowly to destroy excess lithium aluminum hydride. The mixture is diluted with 600 parts ether, washed sequentially with 6N hydrochloric acid, 10 percent aqueous sodium hydroxide, and saturated sodium chloride solution. The organic phase is separated, dried and stripped of solvent, affording 3,5-dipropyl-l,4- benzenedimethanol of suitable purity for chlorination to 3,5-dipropyl-l,4-xylylene dichloride.

PART C 3,5-Dipropyl-l ,4-xylylene dichloride To a solution of 48 parts of 3.5-dipr0pyl-l,4- benzenedimethanol in 200 parts benzene is added a catalytic amount of dimethylformamide and dropwise 57 parts of thionyl chloride. The mixture is refluxed on a steam bath until the evolution of gases ceases. The mixture is stripped of solvent affording suitably pure 3,5-dipropyl-l ,4-xylylene dichloride.

The following l,4-xylylene dichlorides can be prepared from the listed l,4-dibromobenzenes by the reaction sequence shown in Example 8.

cold hexane and water. The isomeric title compounds are separated by fractional crystallization.

By employing the following dialkylmonohaloor dialkyldihalobenzenes in the procedure of Example 9 the following [.3- and 1,4-xylylene dichlorides can be obtained.

EXAMPLE l0 Preparation of 2-Chl0ro-5-propyll ,4-xylylene dichloride. 2-Chloro-3-propyl-l,4-xylylene dichloride, and 2-Chloro-6-propyll ,4-xylylene dichloride To a mixture of 66 parts of 2-propyl-1 4-xylylene dichloride and 5 parts of iodine in 400 parts of carbon tetrachloride is added 23 parts of chlorine. The solution is stirred at room temperature for 6 hours with exclusion of light, then washed with water and dilute sodium bisulfite solution. The organic phase is separated,

2 dried and concentrated. The residue is eluted through TABLE VI" irting Material Product ert-hutyl-S-ethyl-l .4- ltert-butyl-S-ethyl-l .4-xylylene g romobenzene dichloride 7 -diisoprop \'l-l .4- 3.5-diisopropyll .4-xylylene -romohenzene dichloride -di-lert-hutyl-l .4- 3.5-di-tert-hutyll .4-xylylene 'romobenzene dichloride :rt-butyl-S-methyll .4- 3-tert-hutyl-5-methyll .4-xylylene romobenzene dichloride H) -di-sec-hutyll .4- 3.5-di-sec-butyll .4-xylylene romohenzene dichloride :rt-hutyl-S-isopropyl-l .4- 3-tert-hutyl5-isopropyll .4- romohenzene xylylene dichlori e ec-hutyl-S-isopropyll .4- 3sec-but 'l-5-isopropyll .4-xylylene romobenzene dichloride iQpropyI-S-meIhyI-l .4- 3-isopropyl5meth 'l-l .4xylylene l5 romohenzene dichloride ec-hutyl-S-tert-butyl-l .4- 3-sec-hutyl-5-tert-butyll .4-xylylene romohenzene dichloride -diisobutyll .4- 3.5-diisobutyll ,4-xylylene romohenzene dichloride :rt-butyl-S-isobutyl-1.4- 3-tert-butyl-5isohutyll .4-xylylene romohenzene dichloride ec-butyl-S-isohutyl-l .4- 3-sec-hutyl-5-isobutyll 4-xylylene romohenzene dichloride ;obutyl-5 isopropyl l ,4- 3-isobutyl-5-isopropyll A-xylylene romohenzene dichloride :rt-hutyl-S-propyll .4- B-tert-hutyl-S-propyl-l .4-xylylene romohenzene dichloride LZ-dimethylpropyl )-5- propyl-l .4-dihromobenzene 1cthyl-5-l l. l .2 nethylpropyl l .4- romobenzene thyl-5-( H .2.2- 'amethylpropyl )-l .4- romobenzene 34 L'l-dimethylpropyl )-5-isopropyll.4-xylylene dichloride 3-methyl-5-( l. l .Z-trimethylpropyl l.4-xylylene dichloride 3-ethyl-5-( l. l .lltetramethylpropyl )-l .4-xylylene dichloride EXAMPLE 9 -Bromo-3.5-diisopropyl-l,4-xylylene dichloride and 5-Bromo-2,4-diisopropyl-l ,3-xylylene dichloride 5 re given in Rec. Trav. Chim., 85, 457 (l966)] and a column packed with silica gel or Florisil to afford 2- chloro-S-propyl-l,4-xylylene dichloride, 2-chloro-3- propyl-l,4-xylylene dichloride and a small amount of 2-chloro-6-propyl-l,4-xylylene dichloride as three of the fractions.

EXAMPLE 1] Preparation of 4,5-Dichloro-2-propyl-l ,3-xylylene dichloride and 4,6-Dichloro-2-propyl-l ,3-xylylene dichloride To a solution of 50 parts of 4-chloro-2-propyl-l,3- xylylene dichloride in 250 parts of chloroform is added 4 parts of iodine and 16 parts of chlorine. The mixture is refluxed in the absence of light for 5 hours, then washed with water and dilute aqueous sodium bisulfite solution. The chloroform solution is dried and concentrated. The residue is column chromatographed and 4,- 5-dichloro-2-propyll ,3-xylylene dichloride and a small amount of 4,6-dichloro-2-propyl-l,3-xylylene dichlo- 4 5 parts of bis(chloromethyl)ether is treated at -l2C O ride are isolated as two of the fractions. th 260 parts of chlorosulfonic acid. The mixture is The following chlorinated 1,3- and 1.4-xylylene dirred at -l2C for 1 hr and at room temperature for chlorides can be prepared from the listed xylylene di-. nrs. The liquid is drowned in water and washed with chlorides by the procedure of Examples 10 and 1 I.

TABLE IX Starting Material Product l-bromo-2.5-diisopropylbenzene 3-bromo2,5-diisopropyl-1,4-xylylene dichloride 4-bromo-l5-diisopropyll .3-xylylene dichloride l,4-di tert-hutyl-2.5 dichlorobenzene l.S-dihromo-Z.4-diisopropylbenzene l-hromo-2,6-diisopropylhenzene l-chloro-3.S-diisopropylbenzene l-bromo-4-chloro-2,6-diisopropylbenzene l.2-dichloro-3.5-diisopropylhenzene l.4-dibromo-2 .S-dineopentylhenzene l.4-dibrorno-Z-ethyl-5-sec-hutylhe nzene Z-tert-butyll .4-dichloro-5-isopropylbenzene Z-sec-butyll .4-dichloro-5-isopropylhenzene .4-dihromo-Z-isohutyl-S-tert-butylbenzene .S-disec-butyll -chlorohenzene .5-

3 3 3 3 l 4 l l l .5-di-tert-butyl-3.6-dichlorol .4-xylylene dichloride .o-dibromo-3.5-diisopropyll .4-xylylene dichloride hromo-4.6-diisopropyl-l .3-xylylene dichloride -chloro-2.6-diisopropyll .3-xylylene dichloride -chloro 4,6-diisopropyll .3-xylylene dichloride -hromo-Z-chloro-4.6-diisopropyl-l .3-xylylene dichloride .6-dichloro-2.4-diisopropyl-l.3-xylylene dichloride .5 dibromo-3.6-dineopentyl-l .4-xylylene dichloride .5-dibromo-3-ethyl-6-sec-butyll .4-xylylene dichloride -tert-butyl-2.5-dichloro-64sopropyl ,4-xylylene dichloride -sec-hutyldichloro-o-isopropyll .4-xylylene dichloride .S-dibromo. -isohutyl-6-ten-hutyll .4xylylene dichloride .6-di-sec-butyLZ-chlorol .3-xylylene dichloride .6-diisobutyl-Z-chlorol 3-xylylene dichloride -tert-butyl-Z-chloro-(w-ethyll .3xylylene dichloride -sec-hutyl-6-tert-hutyl-2-chlorol .3-xylylene dichloride -chloro-3.S-diisopropyl-l .4-xylylene dichloride -ten-butyl-2-chloro-3-isobutyll .4-xylylene dichloride -bromo4-tert-butyl-Z-isohutyl-l .3-Xylylene dichloride .5-diehloro-2.5-diisopropyll .3-xylylene dichloride ,o-dihromo-2-tert-hutyl-5-isohutyl-l .3-xylylene dichloride TABLE x Starting Material Product Z-isobutyl-l.4-xylylene dichloride i 2 isohutyl-l,4-xvlylenedichloride ZisopropyI- l .4-xylylene dichloride Z-tert-hutyll .4-xylylene dichloride 4-prop \ll .3-xylylene dichloride 4-sec-hutyli .3-xylylene dichloride 'lylene dichloride vlene dichloride 4-isohutyl-l.3 xylylene dichloride 'lene dichloride Z-isopropyll .3-xylylene dichloride 2-eihyll .3-xylylene dichloride S-propyll .3-xylylene dichloride S-isohutyll .3-xylylene dichloride EXAMPLE 12 Preparation of 3,6-Dichloro 2,5 -diisopropyl-1.4-xylylene dichloride 35 sion of light from the reaction vessel. The resulting solution is washed with water, saturated aqueous sodium bisulfite, and water, stripped of solvent and allowed to stand. Pure 3,6-dichloro-2.5-diisopropyl-l.4-xylylene To Suspension of Parts of P Py -L dichloride, m.p. l35-i37C, separates upon standing.

xylylene dichloride and 2 parts of iodine in 350 parts 30 of hexane is added 142 parts of chlorine. The mixture is stirred at room temperature for 10 hours with exclu- By employing the following dialkyl-l,3- and l.4- xylylene dichlorides, these products are obtained.

TABLE Xl Starting Material Product 4chloro-5'-ethyll .3-xylylene dichloride 4-chloro-5 isopropyl-l ,3-xylylene dichloride 4-bromo-5-sec-butyl-l .3-xylylene dichloride 4-chloro-S-isohutyll .3-xylylene dichloride 4-chloro-2-propyll .3-xylylene dichloride 4-hromo-2-sec-hutyll .3-xylylene dichloride 4-chloro-2-isohutyll .3-xylylene dichloride 2-chloro-4-ethyl-l .fi-xylylene dichloride 2-bromo-4-propyll .3-xylylene dichloride 2-bromo-4-isopropyll .3-xylylene dichloride 4-chloro-6-ethyI-l .3-xylylene dichloride 4-tert-but \'l-6-chlorol .3-xylylcne dichloride 4-sec-butyl-6-chlorol .3-xylylene dichloride 2-chloro-6-propyll ,4-xylylene dichloride 2-chloro-6-isobutyll .4-xylylene dichloride 2-hromo-6-sec-hutyll .4-Xylylene dichloride 2-chloro-5-ethyll .4-xylylene dichloride Lchloro-S-isopropyll .4-xylylene dichloride 2-chloro-5 -isobutyll .4-xylylene dichloride 2.5-di-tert-butyll .4-xylylene dichloride 2,5-diisobutyl-l .4-xylylene dichloride 2.5-di-sec-butyl-l ,4-xylylene dichloride Z-isobutyl-S-isopropyl-l .4-xylylene dichloride Z-Sec-buIyI-S-isOpropyI-l .4-xylylene dichloride 3.5-diisopropyl-l .4-xylylen'e dichloride 3.5-diisohutyl-L4- 'lene dichloride 3.5-di-sec-hutvl- 3-isobutyl-5-isopiopyll A-xylylene. dichloride 4,6-diisopropyll .3sx. \'lylene. dichloride 4 6- iisohutyl-l.3-xylylene dichloride.

4I6-di-sec-hutyl-l.3-xylylene dichloride romo-6-chloro-4-isopropyll .3-xylylene dichloride 6-dichloro-4-ethyll .3-xyl \'lene dichloride 4-tert-hutyl-5.6-dichloro l ,3-xylylene dichloride 4-sec-butvl-5 .o-dichlorol .3-xylylene dichloride 2.5-dichloro-3-propyll .4-xylylene dichloride 2,3-dichloro-5-propyl-l.4 'lene dichloride 2.5-dichloro-3-isohutyll .4-xylylene dichloride 2.3-dichloro-5-isobutyll .4-xylylene dichloride -bromo-5-chloro-3-sec-butyll .4-xylylene dichloride -bromo-3-chloro-5-sec-butyll .4-xylylene dichloride .5-dichloro-2-eth \'l- I .4-xylylene dichloride -dichlorosopropyll .4-xylylene dichloride -dichloro-2-isobutyll .4-xylylene dichloride -di-tert-butyl-3.6dichlorol .4-xylylene dichloride -dichloro-2.5-diisohutyll .4-xylylene dichloride -di-sec-hutyl-3.(i-dichlorol .4-xylylene dichloride one! .6-dichloro-3.5-diisopropyll .4-xylylene dichloride .\i-dichloro-3.5-diisohut 'l-l .4-xylylene dichloride .5-di-sec-hutyl-2.(i-dichlorol .4-xvlylene dichloride diehloro-4.6-diisopropyll .3-xylylene chloride .S-dichloro-4.6-diisobutyll .3-xylylene dichloride .fi-di-sec-hutyl-2.5-dichloro-1.3-xylylene dichloride .(i-dichIoro-Z-isohutyl-S-isopropyll .4-xylylene dichloride -sec-hut \'l-3.(i-dichIoro-S-isopropyll .4-xylylene dichloride .6-dichloro-B-isohutyl-S-isopropyll .4-xy2zlene dichloride .5- i

TABLE Xl-Continued Starting Material Product isobutyl-o-isopropyll .3-xylylene dichloride -diisopropyll -diisobutyl-l.3- lS-di-sec-hutyll ,Il-xylylenc dichloride 2-isobutyl-S-isopropyl- I .R-xylylene dichloride l xylylene dichlonde IJIJIJIJ lulu A EXAMPLE 13 Preparation of -Nitro-4-propyl-l ,3-xylylene dichloride Thirty parts of o-nitropropylbenzene is dissolved in parts of chloromethylmethyl ether to which is added dropwise with good agitation 50 parts of 60 percent fuming sulfuric acid [BulL Chem. Soc.. Japan, 43, 3299-3 30l (1970)]. After completion of the vigorously exothermic reaction, the dark reaction mass is taken up in ice water and the product is extracted with benzene. The benzene solution is dried and then decolorized by chromatography on an alumina column. The title compound is recovered by evaporation of the solvent.

The following nitro-l.3-xylylene dichlorides can be prepared from the listed alkylnitrobenzenes by the procedure of Example 13.

TABLE Xll Starting Material Product 4-ten-butyIS-nitrol .3-xylylene dichloride 4-sec-hutyl-5-nitro-l .3-xylylene dichloride 4-ethyl-5-nitrol .3-xylylene dichloride 4--isopropyl-5-nitrol .3-xylylene o-tert-hutylnitrohenzene o-sec-hutylnitrohenzcne o-ethylnitrohenzene o-isopropylnltrobenzene 2.S-dichloro-4-isobutyl-6-isopropyll .3-xylylene dichloride 5.6-dichloro-2.4-diisopropyll .3-xylylene dichloride 5.o-dichloro-Z.4-diisobutyll ,3-xylylene dichloride 2.4-di-sec-butyl-5.6-dichloro-l ,3-xylylene dichloride 5.fi-dichloro-Z-isohutyl-4-isopropyll .3xylylene dichloride 4.6-dichloro-2.S-diisopropyll ,3-xylylene dichloride 4.o-dichloro-2.5-diisobutyll .3-xylylene dichloride 4.6-di'sec-hutyl-4,6-dichloro-1.3-xylylene dichloride 4.6'dichl0ro-Z-isohutyl-5'isopropyll .3-xylylene dichloride Into a refluxing solution of 21.5 parts of 2-ethyl-5- nitroisophthalic acid in 300 parts of tetrahydrofuran is bubbled diborane until the solution is saturated. Reflux is continued for 2 hrs and the solution is kept saturated by addition of diborane. The resulting mixture is cooled. diluted with 600 parts of ether and poured slowly onto ice. The organic phase is separated, washed with water, dilute sodium hydroxide solution and with water. The ethereal solution is separated, dried, and stripped of solvent affording essentially pure 2-ethyl-5- nitro-l ,3-benzenedimethanol.

PART C 2-Ethyl-5-nitro-l ,3-xylylene Dichloride To a solution of 21 parts of 2-ethyl-5-nitro-l ,3- benzenedimethanol in 100 parts of benzene is added a catalytic amount of dimethylformamide and dropwise 24 parts of thionyl chloride in 25 parts of benzene. The mixture is refluxed until evolution of gases ceases. The solvent is evaporated under reduced pressure affording suitably pure 2-ethyl-5-nitro-1,3-xylylene dichloride for conversion to 2-ethyl-5-nitro-l ,3- benzenediacetonitrile.

I dichlmid? I The l,3-xylylene dichlorides of Table Xlll are preo-tertam lnrtrobenzene 4-tert-amyl-5-nltro-l .3-xylylene dichloride pared by the sequence of reactions outlined in Example o-isobutylnitrobenzene 4-isohutyl-5-nitro-1.3-xylylene 40 4 parts in which the listed z alkylisophthalic dichloride acid IS substituted for Z-ethyhsophthahc acid.

TABLE Xlll Z-Alkylisophthalic Acid S-Nitro-Z-alkyll ,3-xylylene dichloride 2-propylisophthalic acid 2-propyl-5-nitr0- l ,3-xylylene dichloride Z-isopropylisophthalic acid Z-isopropyl-S-nitro-l.3-xylylene dichloride 2-isohutylisophthalic acid 2-isohutyl-5-nitrol .3-xylylene dichloride Z-sec-hutylisophthalic acid Z-sec-butyl-S-nitrol .3 xylylene dichloride 2-tert-butylisophthalic acid Z-tert-butyl-S-nitro-l.3-xylylene dichloride 2-( l.2-dimethylpropyl )isoph- 2-( LZ-dimethylpropyl l-5-nitro-l .3-xylylene thalic acid dichloride EXAMPLE l4 EXAMPLE 15 Preparation of 2-Ethyl-5-nitro-l,3-xylylene Dichloride PART B 2-Ethyl-5-nitro-l ,3-benzenedimethanol Preparation of 2,5-DiisobutyI-l ,4-benzenediacetonitrile Into a mechanically stirred suspension of 10 parts of finely powdered sodium cyanide in 55 parts of dimethyl sulfoxide is added in small portions 20 parts of 2,5-diisobutyl-l,4-xylylene dichloride at 55C. The temperature is controlled by the rate of addition of the dichloride and external cooling. After stirring for 0.5 hr at 55C, the reaction mixture is poured into an ice and water mixture; the precipitate is collected; and the moist filter cake is taken up in methylene chloride and washed three times with dilute hydrochloric acid. The methylene chloride solution is treated with anhydrous magnesium sulfate and decolorizing charcoal. and the filtrate is concentrated on a steam bath. The residue is dissolved in a small volume of ether. and the resulting solution is cooled slowly to 50C. The crystals are col lected. washed with 70C ether and dried at 25C 16 glet. 3.25 ppm methine protons (multiplet, 3.15 ppm) and methyl protons (doublet, 1.31 ppm) in ratio of 112:1:6.

EXAMPLE l8 mm/Hg over P affording 13.2 parts pure 2,5- 5 diisobutyl-l,4-benzenediacetonitrile. m.p. 8789C. Preparation of 2,4.6-Triisopropyl-l ,3benzenediacetonitrile EXAMPLE 16 To a mechanically-stirred suspension of 3.5 parts soy dium cyanide in parts of dimethyl sulfoxide is added Preparation of IO 15 .5111?51f.i if' il rllfillilf22335,? i'ii'fll' i benzenediacetonitrile stirred at 50C for 0.5 hr and, after dilution with ice and To a Solution of H2 P sodium Cyanide in 4 Parts water. the solid is collected, washed thoroughly with of dimethyl Sulfoxide is added portionwise 1 P of H cold water and taken up in methylene chloride. The orp py y y dichlm'ldeganic layer is separated, treated with decolorizing char- The mixture is Stirred hr at Poured lnm coal and anhydrous magnesium sulfate. The filtrate is ice Water affording crude P P concentrated to a small volume and ether is added, dichloro-l .4-benzenediacetonitrile. Recrystallization whereupon cokmess crystals f 2 4 ii 3- from ethanol affords P Product -P- 182048400 benzenediacetonitrile separate. After cooling thoroughly in a bath at 50C, the crystals are collected. EXAMPLE 17 washed with ether at 70C and dried. The yield of the P I diacetonitrile melting at 140l42C is 6.0 parts (91 repdrmon of percent). 4,6-Dnsopropyl-l,3-benzenedtacetomtrlle The NMR Spectrum (CDCMTMS) Shows an arm To a mechanically stirred suspension of parts of ma i ton (singlet, 7.24 ppm), methylene protons sodium cyanide in 200 parts of dimethyl sulfoxide is (singlet, 3.80 ppm), methine protons (heptet. 3.35 added 38 parts of 4,6-diisopropyl-l.3-xylylene dichloppm) and methyl protons (two overlapping doublets. ride in small portions, the temperature being main- 1.46, 1.26 ppm)in the ratio of 1:423:18. tained at 60C by controlling the rate of addition of the 30 dichloride and by means of external cooling. The re- EXAMPLE l9 sulting reaction mixture is stirred at 6065C for 0.5 Preparation of hour and diluted to about 1 liter with ice and water; the 2'Ethl'l'5-"ltm'13benzenediacetonitrlle solid benzenediacetonitrile is collected, washed with To a S0|ution f 9 parts f Sodium Cyanide in 50 Water and dissolved in methylene chloride- The q parts of dimethyl sulfoxide is added portionwise 24.8 0115 layer is Separated, and the Organic layer is treated parts of 2-ethyl-5-nitro-l ,3-xylylene dichloride. The re- Wilh decolorlzing Charcoal and anhydrous magnesium action mixture is stirred at 65C for 0.5 hour then disulfate. After concentration to a small volume, ether is l d ith three times i volume f water, Th l added whereupon colorless crystals of 4,6-diisopropyling white solid is collected and recrystallized from a l,3-benzenediacet0nitrile separate. After cooling thorsuitable solvent, affording pure 2-ethyl-5-nitro-1,3- oughly in a bath at 30C. the crystals are collected, benzenediacetonitrile. washed with ether at 70C and dried. The yield of The following 13- and l,4-benzenediacetonitriles benzenediacetonitrile melting at ll6l 17C is 30.7 are prepared from the listed xylylene dichlorides by parts (64 percent). one or more of the procedures shown in Examples 15 The NMR spectrum (CDCLJTMS) shows aromatic through 19. Selected melting points in degrees centiprotons (singlet, 7.35 ppm), methylene protons (singrade are given in parentheses.

TABLE XlV Starting Material Product 2-ethyl-l.3-xylylene dichloride 2-ethyl'l .3-benzenediacetonitrile Z-propyI-l .3-xylylene dichloride 2-isopropyll .3'xylylene dichloride Z-scc-hutyl-l .3-xylylene dichloride Z-tert-hutyl-1.3-xylylene dichloride Z-isobutyll .3xylylene dichloride Z-ethyll ,4-xylylene dichloride Z-propyll .4-xylylene dichloride Z-isopropyl-l .4-xylylene dichloride Z-sec-hutyl-l ,4-xylylene dichloride Z-tert-butyll .4-xylylene dichloride 2-isobutyll ,4-xylylene dichloride 4-ethyl'l .3-xylylene dichloride 4-propyl-l .3-xylylene dichloride 4-isopropyll ,3-xylylene dichloride 4-sec-butyll .3-xylylene dichloride 4-tert-hutyl-l .3-xylylene dichloride 4-isobutyl-l ,3-xylylene dichloride 5-ethyl-l .3-xylylene dichloride 5-propyl- 1 .3-xylylene dichloride S-isopropyll ,3 xylylene dichloride 5-secbutyl-l .3-xylylene dichloride S-tert-hutyll .3-xylylene dichloride 2-propyll .3-henzenediacetonitrile Z-isopropyll .3-benzenediacetonitrile Z-sec-butyl-l .3-benzenediacetonitrile Z-tert-butyl- .3-henzenediacetonitrile lisopropyl-l .3-benzenediacetonitrile Z-ethyl-l .4-benzenediacetonitrile 2-pr0pyl l .4-henzenediacetonitrile Z-isopropyl-l .4-henzenediacetonitrile lsec-hutyll .4-henzenediacetonitrile Z-tert-butyll .4-hcnzenediacetonitrile Z-isobutyl-l .4-henzcnediacetonitrile 4-ethyl-l .3henzenediacetonitrile 4-propyl l .3-henzenediacetonitrile 4-isopropyll .3-benzenediacetonitrile 4-sec-butyl- I .3-benzenediacetonitrile 4-tert-butyll .3-henzenediacetonitrile 4-isobutyll .3'henzenediacetonittrile S-ethyl-l .3-benzenediacetonitrile S-propyl-l ,3-henzenediacetonitrile S-isopropyll .3-henzenediacetonitrile 5-sec-hutyl-l .3 benzenediacetonitrile 5tert-hutyll .3-henzenediacetonitrile TABLE XIV-Continued Starting Material Prod uct 3-tert-butyl-2.S-dichloro-fa-ethyll ,4-xylylene dichloride 4.6-di-sec-hutyl-Z-chloro-l '4 4,6-diisohutyl-Z-chlorol .3 4-tert-butyl-2chloro-6-ethyl-l .3-xylylene dichloride 4,6-dichloro-2.S-diisopropyL l. xylylene dichloride 2.4-dichloro-6-isopropyl-l,B-xylylene dichloride 6-tert-2 4-dichloro-l.3-xylylene dichloride 6-sec-butyI-2,3dichlorol ,4-xylylene dichloride fi-sec-butyl-Z T-dichloro-L-l xylylene dichloride ,3-dichloro-6 isobutyl-l .4 ylylcne dichloride -hromo--isopropyl-l 'lylene dichloride tert-hutyl-4-chloro-l.3- 'lylene dichloride .-1.6-trieth \'ll .3-xylylene dichloride .-l,6-triisopropyll .3-xylylene dichloride .4.(i-tri-sec-butyll .3-xylylene dichloride 'l-lylene dichloride isopropyl-3.4-dimethyll. fi-tert-butyl-2.4-dimethyl-l 'lylene dichloride t'i-tert-hutyl-l.4-diethyl-l .3-x lylene dichloride 5-tert-butyl-2-( LZ-dimethylpropyl l .S-xylylene dichloride S-sec-butyl-Z-isobutyll .3-x \'lylene dichloride 2-isohutyl-S-tert-pentyLl .3 ylylene dichloride Z-isohutyI-S-t I l .Z-trimethylpropyl l ,3-xylylene dichloride S-nitro-Z-propyl-l ,3-xvlylenedichloride 2-isopropyl-S-nitrol xvlylenedichloride Z-isohutyl-S-nitrod.J-x flenedichloride lseobutyl-S-nitro-l,3- lylenedichloride 2-tert-but \'l-5-nitrol .3 yl \'lenedichloride 2-( LI-dimethylpropyl )-5-nitro-l .3-xylylenedichloride Z-sec-hutyl-S-nitrol ,B-benzenediacetonitrile 2-tert-butyl-5-nitrol .3-benzenediaeetonitrile 2-( l ,2-dimethylpropyl )-5-nitrol .B-benzenediacetonitrile EXAMPLE 5-Chloro-2,4,6-triisopropyl-l ,3-benzenediacetonitrile To a refluxing solution of 28.2 parts of 2,4,6- triisopropyl-l.3-benzenediacetonitrile and a trace of iodine in 500 parts of chloroform is added 7.1 parts of chlorine during 1 hr. The mixture is refluxed for 1 hr with exclusion of light. The reaction mixture is cooled, washed with water, dried, and stripped of solvent in vacuo affording 5-chloro-2,4,6-triisopropyll ,3- benzenediacetonitrile.

The following l,3-benzenediacetonitriles are prepared by the procedure of Example 20 TABLE xv Starting Material Product 2,4.6-triethyll ,3- 5-chloro-2,4,6-triethyll ,3-

henzenediacetonitrile benzenediacetonitrile 2.4,6-triisopropyll ,3- 5-chloro-2,4,6-triiospropryll ,3- henzenediacetonitrile benzenediacetonitrile 2,4,6-tri-sec-hutyl-l .3- 2.4,6-tri-sec-butyl-S-chlorol ,3- benzenediaeetonitrile henzenediacetonitrile 6-isopropyl2.4-dimethyl-1,3- 5-chloro-(i-isopropyl-2,4-dimethylhenzenediacetonitrile l.S-henzenediacetonitrile 6-tert-hutyl-2.4-dimethyl-l,3- S-hromo-o-tert-butyl-2,4-dimethyl- 5O benzenediacetonitrile l .3-benzenediacetonitrile o-tert-hutyl-Z.4diethyll ,3- fi-tert-hutyl-5-chloro-2,4-diethylhenzenediacetonitrile l,3-benzenediacetonitrile EXAMPLE 21 Preparation of 4-sec-Butyl-5-nitro-l ,3benzenediacetonitrile To 50 parts of 90 percent nitric acid at 05C is added, in small portions, 5 parts of 4-scc-butyl-L3- benzenediacetonitrile. The mixture is stirred at O-5C for 2 hrs then is poured onto ice. The resulting solid is collected. washed with water. The crude solid is a mixture of products and can be purified by eluting its through a column packed with silica gel or Florisilaffording as one fraction essentially pure 4-sec-butyl-5- nitro-l ,3-benzenediacetonitrile.

EXAMPLE 22 Preparation of 6-lsopropyl-4-nitro-l ,3-benzenediacetonitrile 7.2 Parts of 4,6-diisopropyl-l,3benzenediacetonitrile is added in small portions with stirring to parts of percent nitric acid at l0 to 5C. The resulting solution is stirred at 5 to 0C for 1.2 hrs, then the temperature is increased to 0 to 5C and the solution stirred for 0.7 hrs. The resulting solution is poured into ice. and the solid material is collected and washed with water. The filter cake is dissolved in methylene chloride; the solution is treated with decolorizing charcoal and anhydrous magnesium sulfate, and the filtrate is con-' centrated to a small volume. Upon addition of ether, the 6-isopropyl-4-nitrol ,3-benzenediacetonitrile crystallizes. After cooling the mixture thoroughly in ice, the product is collected and washed with ether at 40C. The product melts at 88-90C.

The NMR spectrum (CDCl /TMS) shows aromatic protons (two singlets, 8.18, 7.74 ppm), methylene protons (two singlets, 4.18, 3.92 ppm) and methine proton (multiplet, 3.20 ppm) and methyl protons (doublet,

1.32 ppm) in ratio of l:l:2:2:l:6.

EXAMPLE 23 Preparation of 2-Nltro-5-tert-butyll ,3-benzenediacetonitrile To 38 parts of 90 percent nitric acid at 0-5C is added portionwise 5 parts of 5-tert-butyl-l,3- benzenediacetonitrile. The reaction mixture is stirred at 0C for 2 hrs then is poured onto ice. The resulting solid is collected and washed with water. Recrystallization from a suitable solvent affords pure 4-nitro-5- tert-butyl-l ,3-benzenediacetonitrile.

EXAMPLE 24 Preparation of 2,4-Dinitro-5-isobutyl- 1 ,3-benzenediacetonitrile To 80 parts of percent nitric acid is added por- EXAMPLE 25 Preparation of 2,5-dinitro-4-propyl-l .3-benzenediacetonitrile A mixture of 26 parts of 5-nitro-4-propyl-L3- benzenediacetonitrile. 16 parts of nitronium tetrafluoroborate and 80 parts of tetramethylene sulfonc is stirred under reflux and heated until the temperature of the liquid registers l-l 15. This temperature is maintained for 1 hour and the mixture is then cooled and poured into crushed ice. The product is removed by filtration and is purified by recrystallization from alcohol.

EXAMPLE 26 3 ,6-Dinitro-2-propyl-l .4-benzenediacetonitrile A mixture of 74 parts of nitronium tetrafluoroborate, 350 parts of tetramethylene sulfone and 105 parts of 2-nitro-6-propyl-l,4-benzenediacetonitrile is stirred under reflux and heated until a thermometer in the liquid registers l00-1 15C. This temperature is maintained for 1 hour and the mixture is then allowed to cool and poured into ice water. The solid product is removed by filtration.

EXAMPLE 27 4,6-Diisopropyl-2-nitro-l ,3-benzenediacetonitrile and 4,6-Diisopropyl-5-nitrol ,3-benzenediacetonitrile To a solution of 12 parts (0.05 mole) of 4,6- diisopropyl-l ,3-benzenediacetonitrile in 25 parts of anhydrous tetramethylene sulfone is added 6.5 parts (0.05 mole) of anhydrous nitronium tetrafluoroborate. The mixture is stirred /2 hour at room temperature and then poured into 200 parts of ice water. The resulting solid is collected and by means of fractional crystallization or by elution through a column packed with silica gel or Florisil is separated into two isomers, 4,6-

diisopropyl-Z-nitro-l.3-benzenediacetonitrile and 4.6- diisopropyl-S-nitrol ,3-benzenediacetonitrile.

EXAMPLE 28 Preparation of 2-Chloro-o-isobutyl-3-nitro-l ,4-benzenediacetonitrile and 2-Chloro-6-isobutyl-5-nitrol ,4-benzenediacetonitrile To 100 parts of 90 percent nitric acid is added portionwise parts of 2-chloro-6-isobutyl-l ,4- benzenediacetonitrile at such a rate that the temperature does not exceed 30C. The mixture is stirred for 2 hr at ambient temperature then poured into ice water. The organic phase is extracted with ether and the extract washed in turn with 2 percent NaOH until free of acid and then with water. The ethereal solution is dried and stripped of solvent by vaccuum distillation. The residue consists of a mixture of positional isomers which can be separated by eluting through a column packed with silica gel or alumina to afford essentially pure 2-chloro-6-isobutyl-3-nitro-l ,4- benzenediacetonitrile and 2-chloro-6-isobutyl-S-nitrol.4-benzenediacetonitrile as separate fractions.

EXAMPLE 29 Preparation of 3-Chloro-2,5-diisobutyl-6-nitro-l .4- benzenediacetonitrile To 38 parts of 90 percent nitric acid is added portionwise 5 parts of 3-chloro2.S-diisobutyl-l .4 benzenediacetonitrile at such a rate that the temperature does not exceed C during the addition. The mixture is stirred at room temperature for 6 hr then warmed on a steam bath for V2 hr. The cooled solution is poured into ice water and the organic phase extracted with ether. The ethereal extract is washed sequentially with water, 2 percent sodium hydroxide, and water, then is dried and the solvent removed by vacuum distillation. The residue is recrystallized. affording pure 3-chloro-2.5-diisobutyl-6-nitro-l .4- benzenediacetonitrile.

The nitrated benzenediacetonitriles of Table XVl can be prepared by nitrating the listed 1,3- or 1,4- benzenediacetonitrile by one or more of the procedures shown in Examples 21, through 29. For cases in which more than one positional isomer is possible separation can be effected by any of a number of physical methods including chromatography, fractional crystallization and distillation.

TABLE XVI Starting Material Product 4-ethyl-S-nitro-l .3-henzenediacetonitrile- 4-propyl-5-nitrol .3-henzenediacetonitrile 4-isopropyl-5-nitro-l .3-henzenediacetonitrile 4-isohutyl-2-nitro- 1 .3-benzenediacetonitrile 4-tert butyl-2-nitro-l .3-henzenediacetonitrile 4-sec-butyl-2-nitro l .3-benzenediacetonitrile 2-isopropyl-4-nitro-l .3-henzenediacetonitrile 2-ten-butyl-4-nitrol .3-henzenediacetonitrile 2-sec-hutyl-4-nitrol .B-henZenediacetonitrile 4-nitro-2-propyl-l .3-henzenediacetonitrile 2.4-diisopropyl-l .3-benzenediacetonitrile Z-tert-hutyl-4-isopropyl-I .3-benzenediacetonitrile Z-scc-butyl-4-isopropyl-l .3-benzenediacetonitrile 5-propyll .3-benzenediacetonitrile 5-lsopropyll .3-henzenediacetonitrile 5-isohutyll .3 benzenediacetonitrile S-see-hutyll .3-henzenediacctonitrile 2-isopropyl-4.6-dinitro-l .I i-benzenediacetonitrile 2-tert-hutyl-4.o-dinitrol .J-henzenediacetonitrile 2-sec-hutyl-4.6-dinitrol .3-henzenediacetonitrile 4-nitro-5-propyl-l .S-henzenediacetonitrile 5-isopropyl-4-nitrol .3-benzenediacetonitrile 5-isohutyl-4-nitrol .3-benzenediacetonitrile 5-scc-hutyl-4-nitro-l .3-henzenediacetonitrile 

1. A METHOD OF CONTROLLING UNDESIRABLE VEGETATION, SAID METHOD COMPRISING APPLYING TO THE LOCUS OF SAID UNDESIRABLE VEGETATION AN HERBICIDALLY EFFECTIVE AMOUNT OF AT LEAST ONE COMPOUND REPRESENTED BY THE FORMULA:
 2. A method of claim 1 wherein undesirable vegetation is selectively controlled in the presence of crops.
 3. The method of claim 1 wherein each of R2; R4, R5, R6, R7, and R8 in the formula of the active ingredient is hydrogen.
 4. The method of claim 3 wherein the active ingredient is 2,5-diisobutyl-1,4-benzenediacetonitrile.
 5. The method of claim 3 wherein the active ingredient is a mixture of 2-tert-butyl-5-isopropyl-1,4-benzenediacetonitrile, and 2-tert-butyl-5-isopropyl-1,3-benzenediacetonitrile. 